MF 1100 Front Pump Seal Leak

[Kitt]

Last Spring I was looking to replace the seal in the front hydraulic pump of my MF 1100. It was leaking about 5 gals per year. However I noticed it didn't seem leak much when actually running, but dripped after shutdown. I've been in the habit of lifting the unloading valve before I cool and shut down the engine. For the last 8 months or so, I've left the unloading valve down and don't use it at start up. Perkins starts easily hot or cold with unload valve down. I haven't added any hydraulic oil since, and only see an occasional drop. I'm guessing that running with unloading valve up removes pressure from the seal lip and it leaks when stopped? The seal is surely worn after 50+ years. I'm not going to replace it now to save a few drops. May have to later. Posting FYI. Maybe it will save someone else some work. Wishing all Merry Christmas!!